Techniques for Accelerating Recovery of Asphalt Emulsion Residues at 60°C by Using Thin Film Procedures and Test Methods Suited to the Limited Amount of Residue Obtained to Characterize the Recovered Binder

Typical procedures to recover residues from asphalt emulsions require a distillation to 260°C + 5°C (500°F) followed by a 15-min hold at that temperature (ASTM D6997). This procedure has served the emulsion industry well for many years, but the advent of polymer modified emulsion (PME) more than 20 years ago lead to modifications of the standard distillation procedure. The realization that some polymers are degraded by the high-temperature distillation procedure and the subsequent loss of the elastomeric properties for which the emulsions were originally produced has resulted in the development over the years of several alternate procedures to obtain the asphalt emulsion residues in an ongoing effort to obtain residues that more closely match those of the base asphalt and especially do not result in the reduction of the elastomeric properties of the emulsion residue. The information reported in this paper utilizes a variant on existing procedures by heating a thin emulsion film at 60°C (140°F) but employing a vacuum (88- to 114-mm Hg pressure, 12 to 15 kPa) for 3 h to obtain the residue. Comparison testing of residues so obtained to base asphalt properties is disclosed showing generally little degradation or stiffening of residues compared to the base binder. Further testing using a newly developed 4-mm dynamic shear rheometer (DSR) test procedure enables determination of the low-temperature PG grade of the emulsion residue without the need of obtaining the quantity of binder needed to perform a conventional bending beam rheometer test on the residue. Also reported in this paper is a novel emulsion residue recovery procedure using a DSR to break, cure and test the emulsion residue stiffness and elasticity (where appropriate) in a single continuous process.

Language

  • English

Media Info

  • Media Type: Web
  • Features: Figures; Photos; References; Tables;
  • Pagination: pp 90-114
  • Monograph Title: Progress Toward Performance-Graded Emulsified Asphalt Specifications
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 01521735
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Apr 8 2014 8:50AM